Residual-current circuit breaker

Abstract

A compact residual-current circuit breaker constructed for functional testing without any interruption of the downstream electric network includes two separate tripping circuits, wherein a first tripping circuit is independent of the mains voltage and a second tripping circuit is dependent on the mains voltage. During functional testing one of the tripping circuits the respective other tripping circuit monitors the electric network to be protected for fault currents.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application claims the benefit of prior filed U.S. provisional Application No. 61 / 387,231, filed Sep. 28, 2010, pursuant to 35 U.S.C. 119(e), the content of which is incorporated herein by reference in its entirety as if fully set forth herein.[0002]This application also claims the priority of Austrian Patent Application, Serial No. A 1620 / 2010, filed Sep. 28, 2010, pursuant to 35 U.S.C. 119(a)-(d), the content of which is incorporated herein by reference in its entirety as if fully set forth herein.BACKGROUND OF THE INVENTION[0003]The present invention relates to a residual-current circuit breaker.[0004]The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.[0005]Residual-current circuit breakers usually have a testing device in order to check the effectiveness of trippi...

AI Technical Summary

Benefits of technology

[0010]A residual-current circuit breaker can be formed thereby in which a functional test can be performed without such a test inevitably leading to an interruption of the current flow in the downstream electric network. Since the renewed programming of electronic appliances as a consequence of a power failure can be avoided, the functional test of such residual-current circuit breakers will have a higher acceptance than the functional test of conventional residual-current circuit breakers. As a result, effective residual-current circuit breakers will be detected at an earlier time than before and can be exchanged. In this way, the security of electric installations will increase. As a result, the functional test can be performed in an automated way at specific points in time by the respective residual-current circuit breaker.

[0011]By arranging the first tripping circuit as a tripping circuit independent of mains voltage which monitors the electric circuit to be protected in the normal operation of the residual-current circuit breaker concerning occurring fault currents, such a residual-current circuit breaker can also be used in countries which have respective national or regional regulations concerning the required use of residual-current circuit breakers which are independent of mains voltages. As a result of the dependency of the second tripping circuit on mains voltage, the second residual-current sensor can be provided with a smaller configuration than the first residual-current sensor since the second residual-current signal determined by the second residual-current sensor can be less powerful as a result of the subsequent active signal amplification than the first residual-current signal which is determined by the first residual-current sensor. The second residual-current sensor can be provided with a much smaller and more compact configuration especially in the case of a preferred configuration of the first and the second residual-current sensor as a summation current transformer. Furthermore, lower requirements are placed on the employed core material, so that the costs for a second residual-current sensor arranged in this manner will be low. Consequently, the overall size of the residual-current circuit breaker can be kept at a low level. The pertinent residual-current circuit breaker is a so-called residual-current circuit breaker which is independent of mains voltage despite the dependence of the second tripping circuit on mains voltage since mains voltage is only required during the process of the functional test and only for this process, as is the case in all residual-current circuit breakers with a respective functional test.

Problems solved by technology

Furthermore, lower requirements are placed on the employed core material, so that the costs for a second residual-current sensor arranged in this manner will be low.

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